Question: Simplify the following expression: $n = \dfrac{t^2 + 13t + 36}{t + 4} $
Solution: First factor the polynomial in the numerator. $ t^2 + 13t + 36 = (t + 4)(t + 9) $ So we can rewrite the expression as: $n = \dfrac{(t + 4)(t + 9)}{t + 4} $ We can divide the numerator and denominator by $(t + 4)$ on condition that $t \neq -4$ Therefore $n = t + 9; t \neq -4$